Development of an image receiving system and an imaging system that handle an ultra-high-definition video signal which overwhelms a high-definition (HD) signal, that is, an existing video signal (image signal) in which one frame has 1920 samples on each of 1080 lines has made progress. For example, ultra-high-definition television (UHDTV) specifications that constitute a new-generation broadcasting method of handling four times or sixteen times larger the number of pixels than an existing HD broadcasting method have been proposed to or standardized by the International Telecommunication Union (ITU) or the Society of Motion Picture and Television Engineers (SMPTE). Video specifications having been proposed to the ITU or SMPTE describe a video signal of 3840 samples×2160 lines or 7680 samples×4320 lines that represents twice or four times larger the numbers of samples and lines than a signal of 1920 samples×1080 lines does. The specifications having been standardized by the ITU are called the large screen digital imagery (LSDI) standard, and the specifications having been proposed to the SMPTE are called the ultra-high-definition TV (UHDTV) standard. As for the UHDTV, signals listed in Table 1 below are specified.
TABLE 1Luminance perNumber ofeffective lineeffectiveFrameSystemor Number oflines perratecategorySystem nameR′G′B′ samplesframe(Hz)UHDTV13840 × 2160/50/P38402160503840 × 2160/59.94/P3840216060/1.0013840 × 2160/60/P3840216060UHDTV27680 × 4320/50/P76804320507680 × 4320/59.94/P7680432060/1.0017680 × 4320/60/P7680432060
As an interface for the signals, a method of transmitting a video signal over a transmission line of a bit rate of 10 Gbps using two channels has been proposed for a video signal of 3840 samples/60 frames conformable to the UHDTV standard. A method of transmitting a video signal over the transmission line of the bit rate of 10 Gbps using eight channels has been proposed for a video signal of 7680 samples/60 frames.
In a patent document 1, a technology for serially transmitting a 3840×2160/30P,30/1.001P/4:4:4/12-bit signal that is a kind of 4 k×2 k signal (an ultra-high-definition signal of 4 k samples×2 k lines) at a bit rate of 10 Gbps or more is disclosed. The wording of 3840×2160/30P refers to the number of pixels in a horizontal direction×the number of lines in a vertical direction/the number of frames per sec. The same applies to the remaining part of this description. Further, 4:4:4 refers to the ratio of a red signal R to a green signal G to a blue signal B in case of a primary-color signal transmission method, or refers to the ratio of a luminance signal Y to a first color-difference signal Cb to a second color-difference signal Cr in case of a color-difference signal transmission method.    Patent document 1: JP-A-2005-328494